efi: Add efi_test driver for exporting UEFI runtime service interfaces

This driver is used by the Firmware Test Suite (FWTS) for testing the UEFI
runtime interfaces readiness of the firmware.

This driver exports UEFI runtime service interfaces into userspace,
which allows to use and test UEFI runtime services provided by the
firmware.

This driver uses the efi.<service> function pointers directly instead of
going through the efivar API to allow for direct testing of the UEFI
runtime service interfaces provided by the firmware.

Details for FWTS are available from,
<https://wiki.ubuntu.com/FirmwareTestSuite>
Signed-off-by: NIvan Hu <ivan.hu@canonical.com>
Cc: joeyli <jlee@suse.com>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>

MAINTAINERS

@@ -4583,6 +4583,13 @@ M:	Peter Jones <pjones@redhat.com>
 S:	Maintained
 F:	drivers/video/fbdev/efifb.c
 
+EFI TEST DRIVER
+L:	linux-efi@vger.kernel.org
+M:	Ivan Hu <ivan.hu@canonical.com>
+M:	Matt Fleming <matt@codeblueprint.co.uk>
+S:	Maintained
+F:	drivers/firmware/efi/test/
+
 EFS FILESYSTEM
 W:	http://aeschi.ch.eu.org/efs/
 S:	Orphan

drivers/firmware/efi/Kconfig

@@ -112,6 +112,23 @@ config EFI_CAPSULE_LOADER
 
 	  Most users should say N.
 
+config EFI_TEST
+	tristate "EFI Runtime Service Tests Support"
+	depends on EFI
+	default n
+	help
+	  This driver uses the efi.<service> function pointers directly instead
+	  of going through the efivar API, because it is not trying to test the
+	  kernel subsystem, just for testing the UEFI runtime service
+	  interfaces which are provided by the firmware. This driver is used
+	  by the Firmware Test Suite (FWTS) for testing the UEFI runtime
+	  interfaces readiness of the firmware.
+	  Details for FWTS are available from:
+	  <https://wiki.ubuntu.com/FirmwareTestSuite>
+
+	  Say Y here to enable the runtime services support via /dev/efi_test.
+	  If unsure, say N.
+
 endmenu
 
 config UEFI_CPER

drivers/firmware/efi/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_EFI_RUNTIME_WRAPPERS)	+= runtime-wrappers.o
 obj-$(CONFIG_EFI_STUB)			+= libstub/
 obj-$(CONFIG_EFI_FAKE_MEMMAP)		+= fake_mem.o
 obj-$(CONFIG_EFI_BOOTLOADER_CONTROL)	+= efibc.o
+obj-$(CONFIG_EFI_TEST)			+= test/
 
 arm-obj-$(CONFIG_EFI)			:= arm-init.o arm-runtime.o
 obj-$(CONFIG_ARM)			+= $(arm-obj-y)

drivers/firmware/efi/test/Makefile

+obj-$(CONFIG_EFI_TEST)			+= efi_test.o

drivers/firmware/efi/test/efi_test.c

+/*
+ * EFI Test Driver for Runtime Services
+ *
+ * Copyright(C) 2012-2016 Canonical Ltd.
+ *
+ * This driver exports EFI runtime services interfaces into userspace, which
+ * allow to use and test UEFI runtime services provided by firmware.
+ *
+ */
+
+#include <linux/version.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "efi_test.h"
+
+MODULE_AUTHOR("Ivan Hu <ivan.hu@canonical.com>");
+MODULE_DESCRIPTION("EFI Test Driver");
+MODULE_LICENSE("GPL");
+
+/*
+ * Count the bytes in 'str', including the terminating NULL.
+ *
+ * Note this function returns the number of *bytes*, not the number of
+ * ucs2 characters.
+ */
+static inline size_t user_ucs2_strsize(efi_char16_t  __user *str)
+{
+	efi_char16_t *s = str, c;
+	size_t len;
+
+	if (!str)
+		return 0;
+
+	/* Include terminating NULL */
+	len = sizeof(efi_char16_t);
+
+	if (get_user(c, s++)) {
+		/* Can't read userspace memory for size */
+		return 0;
+	}
+
+	while (c != 0) {
+		if (get_user(c, s++)) {
+			/* Can't read userspace memory for size */
+			return 0;
+		}
+		len += sizeof(efi_char16_t);
+	}
+	return len;
+}
+
+/*
+ * Allocate a buffer and copy a ucs2 string from user space into it.
+ */
+static inline int
+copy_ucs2_from_user_len(efi_char16_t **dst, efi_char16_t __user *src,
+			size_t len)
+{
+	efi_char16_t *buf;
+
+	if (!src) {
+		*dst = NULL;
+		return 0;
+	}
+
+	if (!access_ok(VERIFY_READ, src, 1))
+		return -EFAULT;
+
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf) {
+		*dst = NULL;
+		return -ENOMEM;
+	}
+	*dst = buf;
+
+	if (copy_from_user(*dst, src, len)) {
+		kfree(buf);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+/*
+ * Count the bytes in 'str', including the terminating NULL.
+ *
+ * Just a wrap for user_ucs2_strsize
+ */
+static inline int
+get_ucs2_strsize_from_user(efi_char16_t __user *src, size_t *len)
+{
+	if (!access_ok(VERIFY_READ, src, 1))
+		return -EFAULT;
+
+	*len = user_ucs2_strsize(src);
+	if (*len == 0)
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * Calculate the required buffer allocation size and copy a ucs2 string
+ * from user space into it.
+ *
+ * This function differs from copy_ucs2_from_user_len() because it
+ * calculates the size of the buffer to allocate by taking the length of
+ * the string 'src'.
+ *
+ * If a non-zero value is returned, the caller MUST NOT access 'dst'.
+ *
+ * It is the caller's responsibility to free 'dst'.
+ */
+static inline int
+copy_ucs2_from_user(efi_char16_t **dst, efi_char16_t __user *src)
+{
+	size_t len;
+
+	if (!access_ok(VERIFY_READ, src, 1))
+		return -EFAULT;
+
+	len = user_ucs2_strsize(src);
+	if (len == 0)
+		return -EFAULT;
+	return copy_ucs2_from_user_len(dst, src, len);
+}
+
+/*
+ * Copy a ucs2 string to a user buffer.
+ *
+ * This function is a simple wrapper around copy_to_user() that does
+ * nothing if 'src' is NULL, which is useful for reducing the amount of
+ * NULL checking the caller has to do.
+ *
+ * 'len' specifies the number of bytes to copy.
+ */
+static inline int
+copy_ucs2_to_user_len(efi_char16_t __user *dst, efi_char16_t *src, size_t len)
+{
+	if (!src)
+		return 0;
+
+	if (!access_ok(VERIFY_WRITE, dst, 1))
+		return -EFAULT;
+
+	return copy_to_user(dst, src, len);
+}
+
+static long efi_runtime_get_variable(unsigned long arg)
+{
+	struct efi_getvariable __user *getvariable_user;
+	struct efi_getvariable getvariable;
+	unsigned long datasize, prev_datasize, *dz;
+	efi_guid_t vendor_guid, *vd = NULL;
+	efi_status_t status;
+	efi_char16_t *name = NULL;
+	u32 attr, *at;
+	void *data = NULL;
+	int rv = 0;
+
+	getvariable_user = (struct efi_getvariable __user *)arg;
+
+	if (copy_from_user(&getvariable, getvariable_user,
+			   sizeof(getvariable)))
+		return -EFAULT;
+	if (getvariable.data_size &&
+	    get_user(datasize, getvariable.data_size))
+		return -EFAULT;
+	if (getvariable.vendor_guid) {
+		if (copy_from_user(&vendor_guid, getvariable.vendor_guid,
+					sizeof(vendor_guid)))
+			return -EFAULT;
+		vd = &vendor_guid;
+	}
+
+	if (getvariable.variable_name) {
+		rv = copy_ucs2_from_user(&name, getvariable.variable_name);
+		if (rv)
+			return rv;
+	}
+
+	at = getvariable.attributes ? &attr : NULL;
+	dz = getvariable.data_size ? &datasize : NULL;
+
+	if (getvariable.data_size && getvariable.data) {
+		data = kmalloc(datasize, GFP_KERNEL);
+		if (!data) {
+			kfree(name);
+			return -ENOMEM;
+		}
+	}
+
+	prev_datasize = datasize;
+	status = efi.get_variable(name, vd, at, dz, data);
+	kfree(name);
+
+	if (put_user(status, getvariable.status)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	if (status != EFI_SUCCESS) {
+		if (status == EFI_BUFFER_TOO_SMALL) {
+			if (dz && put_user(datasize, getvariable.data_size)) {
+				rv = -EFAULT;
+				goto out;
+			}
+		}
+		rv = -EINVAL;
+		goto out;
+	}
+
+	if (prev_datasize < datasize) {
+		rv = -EINVAL;
+		goto out;
+	}
+
+	if (data) {
+		if (copy_to_user(getvariable.data, data, datasize)) {
+			rv = -EFAULT;
+			goto out;
+		}
+	}
+
+	if (at && put_user(attr, getvariable.attributes)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	if (dz && put_user(datasize, getvariable.data_size))
+		rv = -EFAULT;
+
+out:
+	kfree(data);
+	return rv;
+
+}
+
+static long efi_runtime_set_variable(unsigned long arg)
+{
+	struct efi_setvariable __user *setvariable_user;
+	struct efi_setvariable setvariable;
+	efi_guid_t vendor_guid;
+	efi_status_t status;
+	efi_char16_t *name = NULL;
+	void *data;
+	int rv = 0;
+
+	setvariable_user = (struct efi_setvariable __user *)arg;
+
+	if (copy_from_user(&setvariable, setvariable_user, sizeof(setvariable)))
+		return -EFAULT;
+	if (copy_from_user(&vendor_guid, setvariable.vendor_guid,
+				sizeof(vendor_guid)))
+		return -EFAULT;
+
+	if (setvariable.variable_name) {
+		rv = copy_ucs2_from_user(&name, setvariable.variable_name);
+		if (rv)
+			return rv;
+	}
+
+	data = kmalloc(setvariable.data_size, GFP_KERNEL);
+	if (!data) {
+		kfree(name);
+		return -ENOMEM;
+	}
+	if (copy_from_user(data, setvariable.data, setvariable.data_size)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	status = efi.set_variable(name, &vendor_guid,
+				setvariable.attributes,
+				setvariable.data_size, data);
+
+	if (put_user(status, setvariable.status)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	rv = status == EFI_SUCCESS ? 0 : -EINVAL;
+
+out:
+	kfree(data);
+	kfree(name);
+
+	return rv;
+}
+
+static long efi_runtime_get_time(unsigned long arg)
+{
+	struct efi_gettime __user *gettime_user;
+	struct efi_gettime  gettime;
+	efi_status_t status;
+	efi_time_cap_t cap;
+	efi_time_t efi_time;
+
+	gettime_user = (struct efi_gettime __user *)arg;
+	if (copy_from_user(&gettime, gettime_user, sizeof(gettime)))
+		return -EFAULT;
+
+	status = efi.get_time(gettime.time ? &efi_time : NULL,
+			      gettime.capabilities ? &cap : NULL);
+
+	if (put_user(status, gettime.status))
+		return -EFAULT;
+
+	if (status != EFI_SUCCESS)
+		return -EINVAL;
+
+	if (gettime.capabilities) {
+		efi_time_cap_t __user *cap_local;
+
+		cap_local = (efi_time_cap_t *)gettime.capabilities;
+		if (put_user(cap.resolution, &(cap_local->resolution)) ||
+			put_user(cap.accuracy, &(cap_local->accuracy)) ||
+			put_user(cap.sets_to_zero, &(cap_local->sets_to_zero)))
+			return -EFAULT;
+	}
+	if (gettime.time) {
+		if (copy_to_user(gettime.time, &efi_time, sizeof(efi_time_t)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static long efi_runtime_set_time(unsigned long arg)
+{
+	struct efi_settime __user *settime_user;
+	struct efi_settime settime;
+	efi_status_t status;
+	efi_time_t efi_time;
+
+	settime_user = (struct efi_settime __user *)arg;
+	if (copy_from_user(&settime, settime_user, sizeof(settime)))
+		return -EFAULT;
+	if (copy_from_user(&efi_time, settime.time,
+					sizeof(efi_time_t)))
+		return -EFAULT;
+	status = efi.set_time(&efi_time);
+
+	if (put_user(status, settime.status))
+		return -EFAULT;
+
+	return status == EFI_SUCCESS ? 0 : -EINVAL;
+}
+
+static long efi_runtime_get_waketime(unsigned long arg)
+{
+	struct efi_getwakeuptime __user *getwakeuptime_user;
+	struct efi_getwakeuptime getwakeuptime;
+	efi_bool_t enabled, pending;
+	efi_status_t status;
+	efi_time_t efi_time;
+
+	getwakeuptime_user = (struct efi_getwakeuptime __user *)arg;
+	if (copy_from_user(&getwakeuptime, getwakeuptime_user,
+				sizeof(getwakeuptime)))
+		return -EFAULT;
+
+	status = efi.get_wakeup_time(
+		getwakeuptime.enabled ? (efi_bool_t *)&enabled : NULL,
+		getwakeuptime.pending ? (efi_bool_t *)&pending : NULL,
+		getwakeuptime.time ? &efi_time : NULL);
+
+	if (put_user(status, getwakeuptime.status))
+		return -EFAULT;
+
+	if (status != EFI_SUCCESS)
+		return -EINVAL;
+
+	if (getwakeuptime.enabled && put_user(enabled,
+						getwakeuptime.enabled))
+		return -EFAULT;
+
+	if (getwakeuptime.time) {
+		if (copy_to_user(getwakeuptime.time, &efi_time,
+				sizeof(efi_time_t)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static long efi_runtime_set_waketime(unsigned long arg)
+{
+	struct efi_setwakeuptime __user *setwakeuptime_user;
+	struct efi_setwakeuptime setwakeuptime;
+	efi_bool_t enabled;
+	efi_status_t status;
+	efi_time_t efi_time;
+
+	setwakeuptime_user = (struct efi_setwakeuptime __user *)arg;
+
+	if (copy_from_user(&setwakeuptime, setwakeuptime_user,
+				sizeof(setwakeuptime)))
+		return -EFAULT;
+
+	enabled = setwakeuptime.enabled;
+	if (setwakeuptime.time) {
+		if (copy_from_user(&efi_time, setwakeuptime.time,
+					sizeof(efi_time_t)))
+			return -EFAULT;
+
+		status = efi.set_wakeup_time(enabled, &efi_time);
+	} else
+		status = efi.set_wakeup_time(enabled, NULL);
+
+	if (put_user(status, setwakeuptime.status))
+		return -EFAULT;
+
+	return status == EFI_SUCCESS ? 0 : -EINVAL;
+}
+
+static long efi_runtime_get_nextvariablename(unsigned long arg)
+{
+	struct efi_getnextvariablename __user *getnextvariablename_user;
+	struct efi_getnextvariablename getnextvariablename;
+	unsigned long name_size, prev_name_size = 0, *ns = NULL;
+	efi_status_t status;
+	efi_guid_t *vd = NULL;
+	efi_guid_t vendor_guid;
+	efi_char16_t *name = NULL;
+	int rv;
+
+	getnextvariablename_user = (struct efi_getnextvariablename __user *)arg;
+
+	if (copy_from_user(&getnextvariablename, getnextvariablename_user,
+			   sizeof(getnextvariablename)))
+		return -EFAULT;
+
+	if (getnextvariablename.variable_name_size) {
+		if (get_user(name_size, getnextvariablename.variable_name_size))
+			return -EFAULT;
+		ns = &name_size;
+		prev_name_size = name_size;
+	}
+
+	if (getnextvariablename.vendor_guid) {
+		if (copy_from_user(&vendor_guid,
+				getnextvariablename.vendor_guid,
+				sizeof(vendor_guid)))
+			return -EFAULT;
+		vd = &vendor_guid;
+	}
+
+	if (getnextvariablename.variable_name) {
+		size_t name_string_size = 0;
+
+		rv = get_ucs2_strsize_from_user(
+				getnextvariablename.variable_name,
+				&name_string_size);
+		if (rv)
+			return rv;
+		/*
+		 * The name_size may be smaller than the real buffer size where
+		 * variable name located in some use cases. The most typical
+		 * case is passing a 0 to get the required buffer size for the
+		 * 1st time call. So we need to copy the content from user
+		 * space for at least the string size of variable name, or else
+		 * the name passed to UEFI may not be terminated as we expected.
+		 */
+		rv = copy_ucs2_from_user_len(&name,
+				getnextvariablename.variable_name,
+				prev_name_size > name_string_size ?
+				prev_name_size : name_string_size);
+		if (rv)
+			return rv;
+	}
+
+	status = efi.get_next_variable(ns, name, vd);
+
+	if (put_user(status, getnextvariablename.status)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	if (status != EFI_SUCCESS) {
+		if (status == EFI_BUFFER_TOO_SMALL) {
+			if (ns && put_user(*ns,
+				getnextvariablename.variable_name_size)) {
+				rv = -EFAULT;
+				goto out;
+			}
+		}
+		rv = -EINVAL;
+		goto out;
+	}
+
+	if (name) {
+		if (copy_ucs2_to_user_len(getnextvariablename.variable_name,
+						name, prev_name_size)) {
+			rv = -EFAULT;
+			goto out;
+		}
+	}
+
+	if (ns) {
+		if (put_user(*ns, getnextvariablename.variable_name_size)) {
+			rv = -EFAULT;
+			goto out;
+		}
+	}
+
+	if (vd) {
+		if (copy_to_user(getnextvariablename.vendor_guid, vd,
+							sizeof(efi_guid_t)))
+			rv = -EFAULT;
+	}
+
+out:
+	kfree(name);
+	return rv;
+}
+
+static long efi_runtime_get_nexthighmonocount(unsigned long arg)
+{
+	struct efi_getnexthighmonotoniccount __user *getnexthighmonocount_user;
+	struct efi_getnexthighmonotoniccount getnexthighmonocount;
+	efi_status_t status;
+	u32 count;
+
+	getnexthighmonocount_user = (struct
+			efi_getnexthighmonotoniccount __user *)arg;
+
+	if (copy_from_user(&getnexthighmonocount,
+			   getnexthighmonocount_user,
+			   sizeof(getnexthighmonocount)))
+		return -EFAULT;
+
+	status = efi.get_next_high_mono_count(
+		getnexthighmonocount.high_count ? &count : NULL);
+
+	if (put_user(status, getnexthighmonocount.status))
+		return -EFAULT;
+
+	if (status != EFI_SUCCESS)
+		return -EINVAL;
+
+	if (getnexthighmonocount.high_count &&
+	    put_user(count, getnexthighmonocount.high_count))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long efi_runtime_query_variableinfo(unsigned long arg)
+{
+	struct efi_queryvariableinfo __user *queryvariableinfo_user;
+	struct efi_queryvariableinfo queryvariableinfo;
+	efi_status_t status;
+	u64 max_storage, remaining, max_size;
+
+	queryvariableinfo_user = (struct efi_queryvariableinfo __user *)arg;
+
+	if (copy_from_user(&queryvariableinfo, queryvariableinfo_user,
+			   sizeof(queryvariableinfo)))
+		return -EFAULT;
+
+	status = efi.query_variable_info(queryvariableinfo.attributes,
+					 &max_storage, &remaining, &max_size);
+
+	if (put_user(status, queryvariableinfo.status))
+		return -EFAULT;
+
+	if (status != EFI_SUCCESS)
+		return -EINVAL;
+
+	if (put_user(max_storage,
+		     queryvariableinfo.maximum_variable_storage_size))
+		return -EFAULT;
+
+	if (put_user(remaining,
+		     queryvariableinfo.remaining_variable_storage_size))
+		return -EFAULT;
+
+	if (put_user(max_size, queryvariableinfo.maximum_variable_size))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long efi_runtime_query_capsulecaps(unsigned long arg)
+{
+	struct efi_querycapsulecapabilities __user *qcaps_user;
+	struct efi_querycapsulecapabilities qcaps;
+	efi_capsule_header_t *capsules;
+	efi_status_t status;
+	u64 max_size;
+	int i, reset_type;
+	int rv = 0;
+
+	qcaps_user = (struct efi_querycapsulecapabilities __user *)arg;
+
+	if (copy_from_user(&qcaps, qcaps_user, sizeof(qcaps)))
+		return -EFAULT;
+
+	capsules = kcalloc(qcaps.capsule_count + 1,
+			   sizeof(efi_capsule_header_t), GFP_KERNEL);
+	if (!capsules)
+		return -ENOMEM;
+
+	for (i = 0; i < qcaps.capsule_count; i++) {
+		efi_capsule_header_t *c;
+		/*
+		 * We cannot dereference qcaps.capsule_header_array directly to
+		 * obtain the address of the capsule as it resides in the
+		 * user space
+		 */
+		if (get_user(c, qcaps.capsule_header_array + i)) {
+			rv = -EFAULT;
+			goto out;
+		}
+		if (copy_from_user(&capsules[i], c,
+				sizeof(efi_capsule_header_t))) {
+			rv = -EFAULT;
+			goto out;
+		}
+	}
+
+	qcaps.capsule_header_array = &capsules;
+
+	status = efi.query_capsule_caps((efi_capsule_header_t **)
+					qcaps.capsule_header_array,
+					qcaps.capsule_count,
+					&max_size, &reset_type);
+
+	if (put_user(status, qcaps.status)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	if (status != EFI_SUCCESS) {
+		rv = -EINVAL;
+		goto out;
+	}
+
+	if (put_user(max_size, qcaps.maximum_capsule_size)) {
+		rv = -EFAULT;
+		goto out;
+	}
+
+	if (put_user(reset_type, qcaps.reset_type))
+		rv = -EFAULT;
+
+out:
+	kfree(capsules);
+	return rv;
+}
+
+static long efi_test_ioctl(struct file *file, unsigned int cmd,
+							unsigned long arg)
+{
+	switch (cmd) {
+	case EFI_RUNTIME_GET_VARIABLE:
+		return efi_runtime_get_variable(arg);
+
+	case EFI_RUNTIME_SET_VARIABLE:
+		return efi_runtime_set_variable(arg);
+
+	case EFI_RUNTIME_GET_TIME:
+		return efi_runtime_get_time(arg);
+
+	case EFI_RUNTIME_SET_TIME:
+		return efi_runtime_set_time(arg);
+
+	case EFI_RUNTIME_GET_WAKETIME:
+		return efi_runtime_get_waketime(arg);
+
+	case EFI_RUNTIME_SET_WAKETIME:
+		return efi_runtime_set_waketime(arg);
+
+	case EFI_RUNTIME_GET_NEXTVARIABLENAME:
+		return efi_runtime_get_nextvariablename(arg);
+
+	case EFI_RUNTIME_GET_NEXTHIGHMONOTONICCOUNT:
+		return efi_runtime_get_nexthighmonocount(arg);
+
+	case EFI_RUNTIME_QUERY_VARIABLEINFO:
+		return efi_runtime_query_variableinfo(arg);
+
+	case EFI_RUNTIME_QUERY_CAPSULECAPABILITIES:
+		return efi_runtime_query_capsulecaps(arg);
+	}
+
+	return -ENOTTY;
+}
+
+static int efi_test_open(struct inode *inode, struct file *file)
+{
+	/*
+	 * nothing special to do here
+	 * We do accept multiple open files at the same time as we
+	 * synchronize on the per call operation.
+	 */
+	return 0;
+}
+
+static int efi_test_close(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+/*
+ *	The various file operations we support.
+ */
+static const struct file_operations efi_test_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= efi_test_ioctl,
+	.open		= efi_test_open,
+	.release	= efi_test_close,
+	.llseek		= no_llseek,
+};
+
+static struct miscdevice efi_test_dev = {
+	MISC_DYNAMIC_MINOR,
+	"efi_test",
+	&efi_test_fops
+};
+
+static int __init efi_test_init(void)
+{
+	int ret;
+
+	ret = misc_register(&efi_test_dev);
+	if (ret) {
+		pr_err("efi_test: can't misc_register on minor=%d\n",
+			MISC_DYNAMIC_MINOR);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit efi_test_exit(void)
+{
+	misc_deregister(&efi_test_dev);
+}
+
+module_init(efi_test_init);
+module_exit(efi_test_exit);

drivers/firmware/efi/test/efi_test.h

+/*
+ * EFI Test driver Header
+ *
+ * Copyright(C) 2012-2016 Canonical Ltd.
+ *
+ */
+
+#ifndef _DRIVERS_FIRMWARE_EFI_TEST_H_
+#define _DRIVERS_FIRMWARE_EFI_TEST_H_
+
+#include <linux/efi.h>
+
+struct efi_getvariable {
+	efi_char16_t	*variable_name;
+	efi_guid_t	*vendor_guid;
+	u32		*attributes;
+	unsigned long	*data_size;
+	void		*data;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_setvariable {
+	efi_char16_t	*variable_name;
+	efi_guid_t	*vendor_guid;
+	u32		attributes;
+	unsigned long	data_size;
+	void		*data;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_getnextvariablename {
+	unsigned long	*variable_name_size;
+	efi_char16_t	*variable_name;
+	efi_guid_t	*vendor_guid;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_queryvariableinfo {
+	u32		attributes;
+	u64		*maximum_variable_storage_size;
+	u64		*remaining_variable_storage_size;
+	u64		*maximum_variable_size;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_gettime {
+	efi_time_t	*time;
+	efi_time_cap_t	*capabilities;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_settime {
+	efi_time_t	*time;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_getwakeuptime {
+	efi_bool_t	*enabled;
+	efi_bool_t	*pending;
+	efi_time_t	*time;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_setwakeuptime {
+	efi_bool_t	enabled;
+	efi_time_t	*time;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_getnexthighmonotoniccount {
+	u32		*high_count;
+	efi_status_t	*status;
+} __packed;
+
+struct efi_querycapsulecapabilities {
+	efi_capsule_header_t	**capsule_header_array;
+	unsigned long		capsule_count;
+	u64			*maximum_capsule_size;
+	int			*reset_type;
+	efi_status_t		*status;
+} __packed;
+
+#define EFI_RUNTIME_GET_VARIABLE \
+	_IOWR('p', 0x01, struct efi_getvariable)
+#define EFI_RUNTIME_SET_VARIABLE \
+	_IOW('p', 0x02, struct efi_setvariable)
+
+#define EFI_RUNTIME_GET_TIME \
+	_IOR('p', 0x03, struct efi_gettime)
+#define EFI_RUNTIME_SET_TIME \
+	_IOW('p', 0x04, struct efi_settime)
+
+#define EFI_RUNTIME_GET_WAKETIME \
+	_IOR('p', 0x05, struct efi_getwakeuptime)
+#define EFI_RUNTIME_SET_WAKETIME \
+	_IOW('p', 0x06, struct efi_setwakeuptime)
+
+#define EFI_RUNTIME_GET_NEXTVARIABLENAME \
+	_IOWR('p', 0x07, struct efi_getnextvariablename)
+
+#define EFI_RUNTIME_QUERY_VARIABLEINFO \
+	_IOR('p', 0x08, struct efi_queryvariableinfo)
+
+#define EFI_RUNTIME_GET_NEXTHIGHMONOTONICCOUNT \
+	_IOR('p', 0x09, struct efi_getnexthighmonotoniccount)
+
+#define EFI_RUNTIME_QUERY_CAPSULECAPABILITIES \
+	_IOR('p', 0x0A, struct efi_querycapsulecapabilities)
+
+#endif /* _DRIVERS_FIRMWARE_EFI_TEST_H_ */